It's a pretty weird function to have, because if the default was searching for empty fields, you would almost never find anything if you had multiple search fields.
If you really need to enable users to search for certain types of objects with empty values, I'd suggest creating a microflow which takes a bunch of parameters and searches for those.
It's not so weird. The function we use this for is a form where users first insert (often) incomplete data. To take a next step in the workflow they have tot complete the incomplete records and want to search on empty strings, dates, floats etc. en then edit the data.
We already use the suggested work-around.